Safety mechanism for optical projection machines



Dec. 23 1926. 1,612,278

C. L. FITZ SAFETY MECHANISM FOR OPTICAL PROJECTION MACHINES Ori inalFiled Nov. 18, 1922 Patented Dec. 28, 1926.

UNITED STATES PATENT OFFICE.

CHARLES LEO FITZ, OF FOND DU LAC, WISCONSIN, ASSIGNOR TO DROP HEAD "ERO-JECTOR COMPANY, OF FOND DU LAO, "WISCONSIN, A CORPORATION OF WISCONSIN.

SAFETY MECHANISM FOR OPTICAL IP'ROJECTION MACHINES.

Application filed November 18, 1922, Serial No. 601,751.

This invention relates to means for preventing the spread of fire fromwithin the usual encased motion picture machine when the picture filmtakes fire accidentally during use of the machine in a pictureprojection operation.

The present improvement has for its object To provide a structuralformation and combination of parts and elements constituting anautomatic mechanism, interconnected with the enclosing housing and theentry door or doors of a motion picture machine, by means of which theelectric circuit supplying electro-motive force to the electric lampused as an illuminant in the machine, is placed in an open orinterrupted condition while the housing door or doors are in theiropened condition, with such circuit auto-- matically returned to andmaintained in a closed condition, with the closing and latching of saiddoor or doors, all as will hereinafter more fully appear.

In the accompanying drawing:-

Fig. 1 is a side elevation of an enclosed motion picture machineillustrating the application of the invention.

Fig. 2 is a. front elevation of the same.

Fig. 3 is an enlarged detail transverse section on line 33, Fig. 1,showing the preferred construction and arrangement of the combinedlatching and circuit controlling mechanisms of the invent-ion.

Fig. 4 is a detail side elevation of the stationary portion of themechanism on line a a, Fig. 3, with the strike or latch plate removed.

Fig. 5 is a face View of the strike or latcu plate.

Fig. (5 an elevation of the operating knob of the mechanism.

.Fig. 7 is a detached side elevation of the engaging end of the movableportion of the mechanism.

an end olc'mtion of the saline. 9 a diagram showing the light 1 andswitches of the system. Like reference numerals indicate like parts inthe several views.

" Referring to the drawing, 1, designates a portion of the skeletonsupporting frame or structure to which. the central stationary encl singshell 2 of the motion picture machine housing is attached, an example ofwhich is described in detail in a prior appli Renewed May 29, 1926.

cation, Serial No. 598,868, filed Nov. 3, 1922.

3 designates the side doors of the housing, hinged at their rear ends tothe shell 2, in order to afford ready access to the interior of thehousing from its respective sides.

i designates counterpart rectangular extensions fiXed on the skeletonframe 1 near its forward end and adapted to support the stationaryportion of the combined latching and circuit controlling mechanism, nowto he described.

5 designates a bearing bracket attached to the extension 4 and providedwith bearings for a shaft 6, carrying the semi-rotary bar shaped member7 of a circuit closer.

8 and 9 designate a pair of contact fingers mounted in insulatedrelation on the extension l, in the path of the semi-rotary memher 7,and arranged in the hereinafter described electric circuit of thelighting system of the machine. l

10 designates a hub fixedly secured to the forward end of the shaft 6,with its forward end, in turn, formed with a diametric transverse groove11 adapted for operative engagement with the hereinafter describedtongue of the movable portion of the latch mechanism.

12 cl s 'nates a strike or latch plate. fixed on the ension 4 and formedwith slit 13 in aligned relation with the groove 11 of the hub 10, andadapted to permit the entry of the tongue above referred to.

let d signates a semi-rotary hub, forming the main member of the movableportion of the latching mechanism. Said. hub is journalled in anindividual side door 3 of 'the machine housing, and carries at its outerend an operating handle 15, which in the construction shown is formedwith a diametric groove 16 across its face which when filled with amaterial of contrasting color, is adapted to visibly indicate to theoperator the condition of the latch mechanism.

1'7 designates the operating tongue above referred to, of a plate form,and fixedly attached to the inner end of the hub 14-, in longitudinalalignment with the shaft 6, and hub 10 aforesaid. In the presentimprovement the inner end of the tongue 17 is formed with a pair oftransversely projecting lugs 18, which in a movement of the mechanism toa closed position passes through the slit 13 of the latch plate 12, sothat by a quarter turn of the knob 15 by the operator, said lugs 18 areturned crosswise of the slit 13 to lock the two portions of themechanism together with the door in the required closed condition. Insuch turn ing movement of the knob 15, the latch tongue 17 through itsengagement with the hub 10 aforesaid, imparts a simultaneous rotation tothe switch member 7 to establish an electric circuit between the contactfingers or terminals 7 and 8, of the circuit closure mechanismindividual to said indi vidual latching mechanism.

As illustrated in Fig. 9, a separate latching and circuit closingmechanism is provided for each door 3 of the machine housing, with theterminals of the circuit closing port-ions of the mechanisms arranged inseries in the circuit of the lamp 19 used for illumination, so that allthe doors must be closed and latched before current can pass to saidlamp, and thus the main purpose of the invention is attained, towvitzthe prevention ofthc operation of the machine until all the doors areclosed and latched and in order that on an accidental firing of theinflammable picture film, the fire will be confined wholly within themachine casing, which is necessarily formed of metal or like non-fusiblematerial.

Having thus fully described my invention what I claim as new and desireto secure by Letters Patent, is 1. In a safety mechanism for use withthe electrical illuminating means of enclosed optical projectionapparatus, the combination of an enclosing housing provided with anentry door, a latching head mounted for turning adjustment in the doorof a housing, a latch tongue fixed to an end of said head, a revolublecircuit closing mechanism fixedly secured in the interior of saidhousing in aligned relation to said latch tongue and adapted forconnection in an electric circuit, and a keeper plate associated withsaid circuit closing mechanism and having latching engagement with thelatch tongue aforesaid.

2. In a safety mechanism for use with the electrical illuminating meansof enclosed optical projection apparatus, the combination of anenclosing housing provided with entry doors in its side walls, aplurality of latching heads mounted for independent turning adjustmentin the plurality of doors of a housing, latch tongues fixed to ends ofsaid latching heads, a plurality of circuit closing mechanismsindividual to the latching heads and fixedly secured in the interior ofthe housing in aligned relation to said latch tongue, said circuitclosing mechanism being connected in series in an electric circuit andformed with means for operative engagement with the latch tonguesaforesaid, and keeper plates associated with said circuit closingmechanisms and formed for latching engagement with the latch tonguesaforesaid.

3. In a safety mechanism for use with the electrical illuminating meansof enclosed optical projection apparatus, the combination of anenclosing housing provided with an entry door, a latching head mountedfor turning adjustment in the door of a bone-- ing, a latch tongue fixedto one end of said latching head and having lateral end pro jections, arevoluble circuit closing mechanism fixedly attached in the interior ofthe housing in aligned relation to said latch tongue and adapted forconnection in an electric circuit, and a. keeper plate associated withsaid circuit closing mechanism and having a transverse slit adapted forthe entry of and latching engagement with the latch tongue aforesaid.

4, In a safety mechanism for use with the electrical illuminating meansof enclosed optical projection apparatus, the combination ofan enclosinghousing provided with an entry door, a latching head mounted for turningadjustment in the door of a hous m and comprising a circular bodyportion having an operating handle at one end and a flat latch tongue atits other end, said latch. tongue having lateral lugs at its free end,and a keeper plate associated with said circuit closing mechanism andhaving a trans verse slit adapted for the entry of and latchingengagement with the latch tongue aforesaid.

Signed at Fond du Lac, ia, this 16th day of November, 1922.

' CHARLES LEO FITZ.

IGU

